JPH08238943A - Breather device for fuel tank - Google Patents

Abstract

PURPOSE: To allow fuel to be positively filled to a filled-up level without generating the spouting-out of fuel from the breather passage of a fuel tank even in the case of fuel remaining in the breather passage because of a part of the breather passage being positioned lower than a tank side opening end. CONSTITUTION: A diameter-enlarged chamber part 4c positioned higher than a tank side opening end 4a and larger in volume than a part 4b lower than the tank side opening end 4a is interposed in a breather passage 4. At the time of filling fuel, fuel remaining in the part 4b is pushed up into the chamber part 4c, and air in a tank 1 ascends as bubbles in the chamber part 4c so as to be discharged upward, thus maintaining breather function.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breather device mainly applied to a fuel tank for vehicles.

[0002]

2. Description of the Related Art A fuel tank for a vehicle is provided on a lower surface of a floor of a vehicle body, and fuel is injected into the fuel tank from an oil supply port formed on a side surface of the vehicle body through an oil supply pipe. A breather passage with one end open at the same level as the full tank level and the other end open to the atmosphere at the fuel filler port is provided in the fuel tank, and the liquid level in the fuel tank rises to the full tank level when fuel is injected. Until then, the air in the fuel tank can be discharged through the breather passage.

[0003]

The breather passage is generally arranged with a rising gradient of a certain value or more from one end to the other end, but in order to avoid obstacles such as the frame on the lower surface of the floor. There is a case where the breather passage must be diverted below one end thereof, that is, below the opening end on the fuel tank side. When a part of the breather passage is located below the fuel tank side opening end in this way, fuel remains in this portion and the breather passage is closed. When doing so, it becomes impossible to inject fuel to the fuel tank to the full tank level, and if forced to inject, the fuel remaining in the breather passage will blow out from the atmosphere open end of the breather passage due to the increase in internal pressure of the fuel tank. It causes trouble. An object of the present invention is to provide a breather device that solves such a problem.

[0004]

In order to achieve the above object,
The present invention relates to a breather device in which a part of the breather passage opening into the fuel tank is located below the fuel tank side opening end of the breather passage, and the breather passage is located above the fuel tank side opening end. It is characterized in that a chamber portion having a large inner diameter is provided. In this case, it is desirable to make the volume of the chamber portion larger than the volume of the portion of the breather passage located below the opening end on the fuel tank side.

[0005]

When the fuel is injected, the fuel remaining in the portion of the breather passage located below the opening end on the fuel tank side is pushed up to the chamber due to the increase in the internal pressure of the fuel tank.
After that, the air in the fuel tank rises as bubbles in the chamber portion and is discharged above the chamber portion, and the liquid level of the fuel tank rises to the same level as the opening end on the fuel tank side, that is, the full tank level. The internal pressure of the fuel tank does not increase any more until the open end is closed. Therefore, the fuel can be surely injected up to the full tank level, and the residual fuel is not blown out from the breather passage.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment shown in FIG. 1 is an application of the present invention to a breather device for a fuel tank 1 for storing fuel for a combustion heater mounted on an electric vehicle.

The fuel tank 1 is attached to the lower surface of the floor FL of the vehicle body, and an oil supply pipe 2 rising along a wheel house WH of the vehicle body is connected to a side surface portion of the fuel tank 1. In this embodiment, the fuel tank 1 is made of resin, and the oil supply pipe 2 is integrally formed with the fuel tank 1. The upper end of the refueling pipe 2 is connected to a refueling port 3 composed of an adapter attached to a side panel (not shown) of the vehicle body,
The nozzle of the refueling gun G is inserted into the upper end of the refueling pipe 2 through the refueling port 3, and the fuel is injected into the fuel tank 1 through the refueling pipe 2.

Further, a breather passage 4 made of a resin pipe is arranged along the fuel supply pipe 2, and one end of the breather passage 4 is opened in the fuel tank 1 at the same level as the full tank level. At the same time, the other end is opened to the fuel filler port 3 so that the air in the fuel tank 1 can be discharged to the outside through the breather passage 4 at the time of fuel injection.

By the way, a side frame SF is attached to the lower surface of the floor FL, and it is necessary to reduce the height of the lateral outside portion of the fuel tank 1 so as not to interfere with the side frame SF. Therefore, the liquid level rises to the full tank level only in the height portion of the fuel tank 1 located laterally inward of the side frame SF. Since it is necessary to connect the fuel tank side opening end 4a of the breather passage 4 to this height portion, the breather passage 4 is connected to the opening end 4a.
The side frame S is bent once downward from a to form a U-shape.
It is necessary to avoid interference with F.

As a result, when fuel flows into the breather passage 4 from the fuel tank side opening end 4a, the fuel remains in the U-shaped curved portion 4b lower than the opening end 4a as shown in FIG. 1 (a). Become. In this state, the breather passage 4 is closed and the breather function cannot be obtained during the next fuel injection.

Therefore, in this embodiment, the U-shaped curved portion 4b is formed.
A chamber portion 4c having a large inner diameter is formed integrally with the pipe for the breather passage 4 by a blow molding or the like, at a position slightly higher than the fuel tank side opening end 4a at the rising portion from the above. It is desirable that the volume of the chamber portion 4c be larger than that of the U-shaped curved portion 4b.

According to this structure, the fuel remaining in the U-shaped curved portion 4b is pushed up to the chamber portion 4c as shown in FIG. 1 (b) due to the increase in the tank internal pressure due to the injection of the fuel. The air in the tank 1 is the chamber 4c
As bubbles and rise to be discharged above the chamber 4c. Therefore, until the liquid level rises to the full tank level and the fuel tank side opening end 4a is closed, the tank internal pressure does not increase any more, and the fuel can be reliably injected to the fuel tank 1 to the full tank level. In addition, the residual fuel is the chamber portion 4
It will not be pushed up above c and will not cause a problem such as residual fuel being blown into the fuel supply port 3.

Although the breather passage 4 is formed of a single pipe in the above embodiment, as shown in FIG.
The pipe 40, which is inserted inside and has its tip bent upward to open at the same level as the full tank level, and a pipe 41 provided outside the fuel tank 1 are connected via a tube 42 to form the breather passage 4. When configuring, both pipes 40,
The chamber portion 4c formed of a separate container may be interposed between the pipes 41, or the chamber portion 4c may be integrally formed with the outer pipe 41 by blow molding or the like as shown in FIG.

Although the embodiment in which the present invention is applied to the breather device for a fuel tank for a combustion heater provided in an electric vehicle has been described above, a fuel tank for a normal automobile equipped with an engine or a fuel other than that for a vehicle. The present invention can of course be applied to a breather device for a tank.

[0015]

As is apparent from the above description, according to the present invention, the fuel remaining in the breather passage is blown out even if a part of the breather passage is located at a position lower than the opening end on the fuel tank side. It is possible to inject fuel to the full tank level without any trouble.

[Brief description of drawings]

FIG. 1A is a diagram showing a first embodiment of the present invention, and FIG.
The figure which shows the state at the time of lubrication of 1st Example.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

[Explanation of symbols]

 1 Fuel Tank 4 Breather Passage 4a Fuel Tank Side Open End 4b U-Shaped Curved Section 4c Chamber Section

Claims (2)

[Claims] 1. A breather device in which a part of a breather passage opening into a fuel tank is located below an opening end of the breather passage on the fuel tank side, and a portion of the breather passage located above an opening end of the breather passage on the fuel tank side. A breather device for a fuel tank, characterized in that a chamber portion having a large inner diameter is provided in the breather device. 2. The breather device for a fuel tank according to claim 1, wherein the volume of the chamber portion is larger than the volume of the portion of the breather passage located below the opening end on the fuel tank side.